Magnetically operated mercury switch with improved slidable and rotatable magnetic actuators



g- 1956 v G. A. GARIEPY ETAL 3, ,165

MAGNETICALLY OPERATED MERCURY SWITCH WITH IMPROVED SLIDABLE ANDROTATABLE MAGNETIC ACTUATORS Filed Feb. 21, 1963 |N ENT Q5 650265;. A,GAQIELPY O |5 Q. PANNELL.

United States Patent O 3,270,165 lViArGNETICALLY OPERATED MERCURY SWITCHWITH IMPROVED SLIDABLE AND ROTATABLE MAGNETIC ACTUATORS George A.Gariepy, Springfield, and Otis R. Pannell, Alexandria, Va., assignors tothe United States of America as represented by the Secretary of the ArmyFiled Feb. 21, 1963, Ser. No. 260,338 11 Claims. (Cl. 335-54) Theinvention described herein may be manufactured and used by or for theGovernment for governmental purposes without the payment to us of anyroyalty thereon.

The invention herein relates to a magnetically operated mercury switchparticularly adapted for use inside sealed enclosures.

The principal object of this invention is to provide a mercury switchthat can operate through a solid wall without any electrical ormechanical connection between the switch elements on the inside of thewall and the switch handle on the outside.

Another object of this invention is to provide a mercury switch in whichthe working mechanism can be removed and the switch remain constantly ineither its on or off position.

FIG. 1 is a pictorial view of the magnetically operated mercury switchwith a rotating disc mechanism actuating the switch; and

FIG. 2 is a pictorial view of the magnetically operated mercuryswitchwith a sliding bar mechanism actuating the switch.

The switch as shown in FIG. 1 is comprised of two main parts. The firstpart is the rotating handle and switching assembly and the second partis the rocker and vial assembly. Separating the two elements is anon-magnetic plate 15 that might easily be a wall of an enclosurecontaining an explosive media. If the conventional snap switch havingelectrical contacts were used it would be dangerous because this type ofswitch produces a spark when it is snapped between its on and 01fpositions. Here, in this invention the hazard of fire and explosion iseliminated because the handle and the rocker arm assemblages have noelectrical or mechanical connections between them, and the electricalcontacts are sealed within a mercury filled chamber. The entire motivecoupling between the two assemblages is accomplished With permanentmagnets. As there is no necessity for connecting linkage between theinside and outside of the wall this switch can be conveniently usedwhere electrical switching is needed inside an evacuated or pressurizedcompartment.

On one side of the non-magnetic plate the handle and switching elementis found. This assembly is comprised of a circular nonmagnetic member12, L-shaped lugs 5, 6, 7 and 8, handle 11, magnetic poles 1 and 2, andcenter post 10. Center post 10 is welded to the top or outside of platein a normal position to it. Also welded to the plate 15 and equallyspaced about the center post 10 are the four inverted L-shaped lugs 5,6, 7 and 8. Circular disc 12 has a center hole which allows it to heslipped over post 10 and rotate about said post. Around the periphery ofthe plate 12 are notches coinciding to the overlapping portion of thefour lugs. When the disc is in a particular position the disc can belifted off the center post by handle 11 because the notches allow it toslide up past the overhang of lugs 5, 6, 7 and 8. Handle 11 is fastenedto the disc at its center so the disc will be balanced when it is liftedoff.

At diametrically opposite positions of circular disc 12 are recesses toreceive a magnet having a south pole 1 and north pole 2. Across the topof disc 12 is a groove conmeeting the two recesses. With theinterconnecting groove the disc thus is provided with a groove or recessup one edge, across the top and down the opposite edge. This will give asort of a U-shaped groove for a horseshoe type magnet with south pole 1,back member 9, and north pole 2. A widened portion in the back member ofthe magnet and the recess in which it fits provides sufficient metal inthe backing member for strength and for the lines of force in thepermanent magnet. The hole for post 10 enabling disc 12 to rotate goesthrough this widened portion in back member 9.

The rocker and vial assembly 1 is directly below the handle andswitching mechanism and on the opposite side of wall 15. Comprising therocker and vial assembly are;

rocker arm 16, rectangular magnets 3 and 4, rocking pin 13, supports 14and mercury filled vial 17. Rocker arm 16 is rotated about its centerthrough two upturned ears centrally located, each having a hole throughwhich is placed pin 13. At each end of the rocker arm are rectangularmagnets so oriented that the south pole of both magnets are on the topside, the north pole being on the bottom, both of said magnets beingsecured to the ends of the rocker arm. Supports 14 are welded to theunder side of plate 15 and have holes for pin 13 on which rocker arm 16is rotated. The supports 14 are positioned so that the magnets of therocker assembly are directly beneath the magnets of the switching andhandle assembly. This allows the magnet 3 to be either attracted bymagnet 2 or repelled by magnet 1 depending on which position therotating disc is in. Likewise, magnet 4 can be either attracted orrepelled.

Fastened on the bottom of the rocker arm and at its center is themercury filled vial 17. This vial is the conventional vial used in allmercury switches. It has a pair of contact electrodes sealed in one endof the vial and protruding into the inside of said vial. When the vialis tipped in one direction, the mercury all runs to the lowest end. Ifthe two electrodes which are sealed in one end of the vial are at thelower end, the mercury flows down and serves as a conducting mediabetween the two electrodes. Conversely, if the two electrodes are at thehigher end, the mercury flows to the opposite end, leaving no conductorbetween the two electrodes thereby breaking the circuit.

Locking means is necessary to hold the vial and the pivot arm in eitherthe on or off position when the rotating disc 12 is removed. Suchlocking means is comprised of a small piece of ferromagnetic materialembedded in the isolating plate 15 directly above magnet 4. This smallferromagnetic element will cause the magnet to cling to the underside ofplate 15 when the switch mechanism is rotated so that magnet 2 attractsmagnet 4. When magnet 4comes in contact with the small piece offerromagnetic material 18, the magnet clings to it thereby lifting theend of rocker arm 16 having magnet 4. With the rocker arm in thisposition the rotating dis-c containing magnets 1 and 2 can be lifted offthe center post. Removal can be easily accomplished with the discoriented so as to cause magnet 4 to be attracted to magnet 2, be-

cause this is the position of the disc 12 which will allow it to belifted off the retaining lugs 5, 6, 7 and 8. Hence, the lugs provide anorientation guide for the removal of disc 12 which leaves the rocker armlocked either in its on or off position depending on which end of thevial the electrodes are embedded.

A modification of the locking means is brought about by the insertion ofanother small ferromagnetic element in the bottom of plate 15 directlyabove magnet 3. This will give an element for either magnet 3 or 4 tocling to. By revolving circular disc 12 and removing it, the rocker armcan be locked either in the on or off position regardless of which endof the mercury vial the electrodes are embedded. By using two pieces offerromagnetic ma- Patented August 30, 1966 3 terial instead of only onesuch element as 18 explained above, an alternate locking position isachieved.

Still another modification involves leaving the circular disc on thespindle or post all the time. Where all that is needed is momentarycontact instead of sustaining the switch in the on position, thecircular plate with its handle can be spring biased so that it alwaysreturns to its off position when the handle is released.

FIG. 2 shows a different type actuating means for operating the mercuryswitch. Here, the switch is operated by a sliding bar mechanism insteadof a rotating plate. Beneath wall the rocker arm and vial assembly isidentical with the rocker arm and vial assembly of the switch shown inFIG. 1. The difierence over the rotating disc switch is above wall 15where a sliding T-shaped member 24 carrying permanent magnets 19, 20 and21 embedded within it actu-ates the rocker arm assembly. The rectangularpermanent magnets have alternating poles adjacent to wall 15. Magnet 20has its negative pole adjacent to wall 15 while magnets 19 and 21 havetheir positive poles adjacent to the wall 15. Connecting all three ofthe magnets is a ferromagnetic strip 23 embedded in the top of slidingbar 24. A U-shaped guide permits the sliding bar to be moved back andforth but prevents lateral movement of the bar. This guide holds thesliding bar in position so that the magnets embedded within the bar aredirectly over the magnets of the rocker arm assembly when the slidingbar is at either of its two extreme positions. A pair of stops 22 serveto limit the movement of the sliding bar and also guide the bar in itsreciprocal motion. The narrow handle portion at one end of the slidingarm is easily grasped to manually operate the switch.

When the sliding arm is positioned with the wide portion butting againstthe stops 22, the whole sliding arm can be removed by lifting itvertically off wall 15. A small piece of ferromagnetic material 18 isembedded within the bottom surface of wall 15 directly above magnet 3.When the sliding bar is pulled into its removal position, magnet 20which is negative attracts magnet 3 which is positive. Rocker arm 16will rotate and magnet 3 will swing up until it is in contact with theunderside of wall 15. Upon contact with wall 15 at the point where thepiece of ferromagnetic material 18 is embedded magnet 3 will cling tothe underside of wall 15. Sliding bar 24 can then be removed withoutdisturbing the angular position of the vial 17. Removal of the slidingbar eliminates the accidental actuation of the switch because of thepositive action required to turn the switch on and off. The sliding armmust be inserted before the switch can be moved. Also, with the slidingarm removed, the switch is somewhat tamperproof because the switch canonly be turned on or oil with the sliding bar or a similar arrangementof magnets. In both of these respects the magnetically operated mercuryswitch is much safer than a switch such as the toggle type.

Operation of the switch is accomplished by inserting the sliding bar 24in position between guide 22 and guide 25 and pushing the bar to theright until magnet 19 is directly over magnet 3. Magnet 19 beingpositive and magnet 3 being positive, these magnets will repel and themagnetic repulsion will be greater than the attraction of magnet 3 forthe embedded ferromagnetic material 18. The rocker arm 16 will thenswing to its other extreme and will be stopped when magnet 4 contactsthe underside of wall 15, and the mercury in vial 17 will run to theopposite end either making or breaking electrical contact.

We claim:

1. An electrical switch comprising:

(a) A mercury filled vial having .two electrodes sealed in one end andmounted on one side of a non-magnetic supporting wall through tiltablevial supporting means;

(b) A movable support member for a series of permanent magnets, saidsupport member being mounted the opposite side of the supporting walland having guide means allowing said movable member to be removed fromthe supporting wall; and

(c) Permanent magnets carried by said movable support member andtiltable vial supporting means capable of magnetically coupling themovable support member to said tiltable vial support means.

2. An electrical switch comprising:

(a) A mercury filled vial with two electrodes sealed in one end of thevial, said vial being mounted on one side of a non-magnetic supportingwall through tiltable supporting means;

(b) A removable circular disc rotatably mounted on the opposite side ofsaid wall by means of a center post normal to the wall, said disc havingorientation and guide means for its removal; and

(c) Magnets within said circular disc and vial supporting means capableof magnetically coupling the rotating disc to said tilting vial supportmeans.

3. An electrical switch comprising:

(a) A circular nonmagnetic disc having a series of peripherial notchesand a permanent U-shaped magnet with spaced poles projecting downwardfitted within a U-shaped recess within the top of said circular disc,said disc having an axial hole through its center;

(b) A center circular post for the circular disc to rotate about,attached to and also normal to a nonmagnetic supporting wall for theswitch;

(c) Inverted L-shaped lugs welded to the sides of the wall having thecenter post with the overhanging lips of the lugs facing the center postand mating with the peripherial notches of the circular disc;

(d) A rocker arm assembly pivotally supported on the side of the supportwall opposite the circular disc;

(e) A vial partially filled with mercury and having two electrodessealed in one end, said vial being fastened to the center of the rockerarm; and

(f) A rectangular magnet secured to each end of the rocker arm, saidmagnets having like poles nearest the supporting wall, said like polesbeing diametrically opposed to the poles of said U-shaped magnet withinsaid circular disc.

4. An electrical switch comprising:

(a) A rocker assembly of (1) a mercury filled vial having two electrodessealed in one end,

(2) a rocker arm supporting said mercury filled vial, said rocker armpivotally connected to one side of the non-magnetic wall supporting theswitch,

(3) a rectangular magnet at each end of the rocker arm, each magnethaving like poles closest to the supporting wall; and

(b) A rotating magnet assembly of (1) a circular non-magnetic discgrooved to receive .a horseshoe magnet having Widely spaced poles, saiddisc having a series of notches about its periphery and a handle forlifting,

(2) a center post welded to the supporting wall and normal to it aboutwhich the circular disc can rotate, said post being welded to the sideof the supporting wall opposite from the side with the rocker armassembly,

(3) and a series of inverted L-shaped lugs equidistant about the saidpost and mated to the peripherial notches in the circular disc.

5. An electrical switch as claimed in claim 3 having a ferromagneticelement embedded in the supporting wall directly above one of therectangular magnets of the rocker arm assembly.

6. An electrical switch as claimed in claim 3, having a ferromagneticelement embedded in the supporting wall directly above each rectangularmagnet of the rocker arm assembly.

7. An electrical switch as claimed in claim 3, in which the rotatablecircular disc is spring biased.

8. An electrical switch comprising:

(a) A T-shaped sliding bar of non-magnetic material slidably mounted on:and removable from one side of a non-magnetic supporting wall, saidT-shaped sliding bar having recessed in one face three spacedrectangular permanent magnets, the center magnet having its negativepole exposed on one face of said T-shaped bar, and the two end magnetshaving their positive poles exposed on the same face surface of said T-shaped bar;

(b) A U-shaped guide secured to the supporting wall, said U-shaped guidereceiving a first portion of said T-shaped bar and allowing the T-shapedbar to be reciprocally moved while having its surface containing theexposed poles of said permanent magnets in face relationship with thesupporting wall;

() A pair of spaced guide stops secured to the supporting wall andspaced to receive a second portion of said T-shaped bar;

(d) A rocker arm assembly pivotally supported on the side of the supportwall opposite said T-shaped bar;

(e) A vial partially filled with mercury and having two electrodessealed in one end, said vial being fastened to the center of said rockerarm; and

(f) A rectangular magnet secured to each end of said rocker arm, saidmagnets having like poles nearest the supporting wall.

9. An electrical switch comprising:

(a) A removable sliding bar carrying a series of permanent magnetsspaced along said bar, each magnet 6 being so oriented that its polesare reversed from the magnet adjacent to it;

(b) Guide means to limit said sliding bar to reciprocal movement alongone side of a non-magnetic supporting wall; and

(c) A rocker arm assembly mounted on the opposite side of the supportingwall, said rocker arm assembly comprising a pivoted rocker arm, amercury vial switch element attached to said rocker arm, and permanentmagnets fixed to said rocker assembly that are attracted or repel-led bythe permanent magnets of the sliding bar in such a manner as to causethe rocker arm and mercury vial to be tilted when the sliding bar ismoved in either direction.

10. An electrical switch as claimed in claim 8 wherein the nonexposedpoles of the three recessed permanent magnets are connected by aferromagnetic strip recessed along the length of said T-shaped slidingbar.

11. An electrical switch as claimed in claim 8 wherein a piece offerromagnetic material is embedded within the supporting wall directlyabove one of the permanent magnets of said rocker arm assembly.

References Cited by the Examiner UNITED STATES PATENTS 2,577,165 112/1951 Thorsheim 2001 12 X 2,622,136 12/1952 Christensen 200112 X2,634,348 4/ 1953 Tingley 200-112 ROBERT K. SCHAEFER, Primary Examiner.KATHLEEN H. CLAFFY, Examiner. J. R. SCOTT, Assistant Examiner.

2. AN ELECTRICAL SWITCH COMPRISING: (A) AN MERCURY FILLED VIAL WITH TWOELECTRODES SEALED IN ONE END OF THE VIAL, SAID VIAL BEING MOUNTED ON ONESIDE OF A NON-MAGNETIC SUPPORTING WALL THROUGH TILTABLE SUPPORTINGMEANS; (B) A REMOVABLE CIRCULAR DISC ROTATABLY MOUNTED ON THE OPPOSITESIDE OF SAID WALL BY MEANS OF A CENTER POST NORMAL TO THE WALL, SAIDDISC HAVING ORIENTATION AND GUIDE MEANS FOR ITS REMOVAL; AND (C) MAGNETSWITHIN SAID CIRCULAR DISC AND VIAL SUPPORTING MEANS CAPABLE OFMAGNETICALLY COUPLING THE ROTATING DISC TO SAID TILTING VIAL SUPPORTINGMEANS.